The overall objective of this project is to gain an understanding of how the availability of amino acid(s) regulates the rate of RNA synthesis in micro-organisms. Three primary projects for this year are: 1) Deriving a correlation between "%-t-RNA charging, the gross rate of RNA synthesis, and" the rate of protein synthesis. This correlation has been made by others in the past, but only the net rate of RNA synthesis was measured. 2) Attempting to develop a regulated in vitro system of RNA synthesis in extracts of whole E. coli cells. Concentrated, osmotically-sensitive cells will be lysed on cellophane disks. Incorporation mixtures similar to those used successfully in in vitro coupled RNA-protein synthesis will be utilized. 3) Developing a computer simulation model of uptake and incorporation of nucleotides by cells is being pursued. The output will be compared to experimental data. Such a model offers great flexibility in parameter design, and easily allows simulation of "timed" events, such as pulse-chase or "shift" experiments.